De Wet, Johannes H.v.H. (Johannes Hendrik van Heerden); Hall, J.H. (John Henry)(Faculty of Economic and Management Sciences University of Pretoria, 2006-03)
Gouws, Daan G.; Habtezion, A.Y.; Vermaak, Frans N.S.; Wolmarans, Hendrik Petrus(Faculty of Economic and Management Sciences University of Pretoria, 2006-09)